Matrix for extruding metals



July 18, 1933. Q METZGER 1,918,858

MATRIX FOR EXTRUDING METALS Filed June 30, 1932 a, mm.

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Patented July 1s, 19aa UNITED;

METALLWERKE A.-G., ZWEIGNIEDERLA or nunnmznnow, Guam:

m'rnrx' FOB, nx'rnunm'e 1 Application filed June so, ie'sasng no.

. For the warm orcold extrusion-oftubularP articles, such as shells or cups, one-partmatrices are employed, into which a blank: is. inserted, which is shaped into the tubular article by means of-a plunger. Since exceed:

ingly high shaping forces are necessary'for this purpose, the implements, particularly the matrix, are of course also exposed to very heavy stresses. The radial shearing forces occurring in extrusion are so great that matrices made in one piece, after being used only a comparatively small number of times, break in the neighbourhood of the-transition from the horizontal bottom surface upon which the blank lies to the vertical peripheral surface along which the metal squirts up, and therefore soon become useless.

This serious disadvantage is obviated according to the present invention by dividing the matrix in the plane in which the greatest radial forces occur. The matrix therefore consists according to the invention of ansile stresses.- Both the under part of the .35 I consists of an under art 3-and a ring 4-sepmatrix and the ring are held firmly in their positions by a clamping block.

One example of construction of the inven-' tion is illustrated in the accompanying drawin in elevation, partly in section.

matrix for the reception of the blank 1 and of the associated mandrel 2.- The matrix arate therefrom. T e under part 3 has a shallow recess 5 for the reception of the blank 1, and is guided in a cylindrical bore 6 in a clamping block 7. In a slightly conical bore 8 in this block 7 is inserted the ring 4, the internal peripheral surface 9 of which fits accurately to the annular edge 10 of the recess 5. The ring 4 is preferably only in close contact with the under part 3 around the lower edge of its inner peripheral surface 9, this edge resting upon the margin of the recess 5. By screwing the clamping block 7 on to a base 11, the under part 3 of the matrix is pressed upwards, and in its turn 620.234} and it eerma 'n n :0, 1 932..

transmitsgthepressure tog therin'g 4,

thereby pressed firmly into the conical bore 8. By screwing in the base=11',therefore, the

two parts 3va'nd 4 of the *matrix are'held fast in-theclamping block 7 an axial direction. a Since, 'howeverpthe ring-4 'islnOt rigidlycon- .netediwithfthe under part 3, it has freedom of movement in-radial directionswithinthe "limits of elasticity. Now if during the shaping of the blank 1 radial forces of greater or less magnitude, according to the nature of the material tozbe'upwardly extruded, are produced by the plunger 2, these forces act upon the ring 4, which alone receives them. There is therefore in a radial direction some possibility of movement of the ring 4 in relation to the under member 3, though this movement can only be very small. In other words, the radial forces converted into tensile stresses will bring about a change in the shape of the ring, but cannot adversely affect the under part 3, since the shearing forces that occur in the case of matrices made in onev piece can no longer arise at all owing to the separation of the ring from the under partof the matrix. It will be understood that when the conical insertion 4 is very strongly the external radial forces, so a certain initial he implement consists essentially of a.

stress is given to the ring; In extrusion or squirting, however, the radial forces acting from theinside are converted into tensile stresses is considerably increased, so that theformation of cracks in the internal surface is obviated. The tests so far made confirm the I correctness of the opinion concerning these The two-part matrix stress relationships. constructed according to this invention is particularly suitable for the cold extruding of metals such as zinc and aluminium, which require particularly large shaping forces.

As experiments have shown, the life of the matrix according to this invention is considerably longer than that of known matrices.

The division of the matrix into two parts has the advantage that only the ring, which has to stand the highest stresses, need be made of high-grade steel.

What I claim is 1. A matrix for the backward extrusion of metals, consisting of an under part for the reception of a metal blank, a ring, separate from the underpart, and adapted to be superposed thereon and to surround the blank, a clamping block formed with a cylindrical bore adapted to receive the under part of the matrix and with a conical bore adapted to receive the ring, and a base adapted to be screwed into the clamping block, and, when so screwed in, to force the under part of the matrix against the bottom of the ring and thereby to force the ring into its conical bore.

2. A matrix for the backward extrusion of metals, consisting of an under part formed with a shallow recess in its top surface for the reception of a metal blank, a ring, separate from the underpart, and adapted to be superposed thereon with the lower edge of its internal periphery registering with the outer edge of the recess in the under part of the matrix, a clamping block formed with a cylindrical bore adapted to receive the under part of the matrix and with a conical bore adapted to receive the ring, and a base ada ted to be screwed into the clamping bloc and, 'when so screwed in, to force the under part of the matrix against the bottom of the ring and thereby to force the ring into its conical bore.

3. A matrix for the backward extrusion of metals over a co-operating plunger, consisting of an under part for the reception of a metal blank, a ring, separate from the under part, and adapted to be superposed thereon and to surround the blank, this ring only being in close contact with the under part around the lower edge of its inner peripheral surface, a clamping block formed with a cylindrical bore adapted to receive the under part of the matrix and with a conical bore adapted to receive the ring, and a base adapted to be screwed into the clamping block, and, when so screwed in, to force the under part of the matrix against the bottom of the rin and thereby to force the ring into its comcal bore.

OTTO METZGER. 

